Switched mode power supply with precharge of base-emitter sweep-

Details Switched mode power supply with precharge of base-emitter sweep- Switched mode power supply with precharge of base-emitter sweep-

1992-07-22

1994-03-01

Beha, Jr., William H.

Electric power conversion systems

Current conversion

Including d.c.-a.c.-d.c. converter

323289, 363 49, H02M 75375

Patent

active

052913864

ABSTRACT:
A television receiver has a switched mode power supply for regulating an output voltage, including a power transformer having a primary winding coupled to an unregulated voltage via a power transistor. The power transistor is controlled by pulses from the output of a controller. In order to sweep the base-emitter charge from the power transistor in order to end collector-emitter conduction, the base of the power transistor is coupled to the output of the pulse generating controller via a capacitor in parallel with at least one diode. During a pulse from the controller, the capacitor is charged to a voltage equal to the forward biased drop across the diode(s). At the end of a pulse at the output of the controller, the voltage across the capacitor provides a negative voltage at the base of the transistor, thus sweeping out the base-emitter charge and sharply turning the transistor off. In order to assure this function of the capacitor even upon plug-in startup, the capacitor is precharged via a resistor coupled between the output of the controller and the unregulated voltage input.

REFERENCES:
patent: 4312029 (1982-01-01), Zellmer
patent: 4609980 (1986-09-01), Hoffman
patent: 4975823 (1990-12-01), Rilly et al.
Blaesner, "Erhohte Betriebssicherheit und Niedrigere Kosten" Elektronik (Germany), vol. 9, No. 39, pp. 134-140, Apr. 27, 1990.

Affiliated with

Also associated with

Rating

Switched mode power supply with precharge of base-emitter sweep- does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Switched mode power supply with precharge of base-emitter sweep-, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Switched mode power supply with precharge of base-emitter sweep- will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-583262